Microelectronic assemblies, and related devices and methods, are disclosed herein. For example, in some embodiments, a microelectronic assembly may include a package substrate having a first surface and an opposing second surface, and a die secured to the package substrate, wherein the die has a first surface and an opposing second surface, the die has first conductive contacts at the first surface and second conductive contacts at the second surface, and the first conductive contacts are coupled to conductive pathways in the package substrate by first non-solder interconnects.

The subject matter contained herein discloses methods for forming a vertical metallic pillar overlying an under bump metal pad further overlying a semiconductor substrate, and applying a discrete solder cap on a top surface of the pillar, wherein the metallic pillar is defined by at least one photoresist layer. The method includes heating a multi-element metallic paste containing a variable amount of metallic powder, a melting point depressant and a flux such that the metal powder sinters to form the metallic pillar and simultaneously adheres the metallic pillar to the underbump metal pad.

The subject matter contained herein discloses methods for forming a vertical metallic pillar overlying an under bump metal pad further overlying a semiconductor substrate, and applying a discrete solder cap on a top surface of the pillar, wherein the metallic pillar is defined by at least one photoresist layer. The method includes heating a multi-element metallic paste containing a variable amount of metallic powder, a melting point depressant and a flux such that the metal powder sinters to form the metallic pillar and simultaneously adheres the metallic pillar to the underbump metal pad.

An integrated circuit die may be fabricating to have a plurality of contacts. A metal post may be formed on each of the plurality of contacts. A plurality of bumps may be formed on a plurality of contact regions of a leadframe or on the posts, in which the plurality of bumps are formed with a material that includes metal nanoparticles. The IC die may be attached to the leadframe by aligning the metal posts to the leadframe and sintering the metal nanoparticles in the plurality of bumps to form a sintered metal bond between each metal post and corresponding contact region of the leadframe.

An integrated circuit die may be fabricating to have a plurality of contacts. A metal post may be formed on each of the plurality of contacts. A plurality of bumps may be formed on a plurality of contact regions of a leadframe or on the posts, in which the plurality of bumps are formed with a material that includes metal nanoparticles. The IC die may be attached to the leadframe by aligning the metal posts to the leadframe and sintering the metal nanoparticles in the plurality of bumps to form a sintered metal bond between each metal post and corresponding contact region of the leadframe.

A solder connection may be surrounded by a solder locking layer (1210, 2210) and may be recessed in a hole (1230) in that layer. The recess may be obtained by evaporating a vaporizable portion (1250) of the solder connection. Other features are also provided.

A solder connection may be surrounded by a solder locking layer (1210, 2210) and may be recessed in a hole (1230) in that layer. The recess may be obtained by evaporating a vaporizable portion (1250) of the solder connection. Other features are also provided.

A semiconductor device includes an electric conductor, a semiconductor element, and a bonding layer. The electric conductor has a main surface and a rear surface opposite to the main surface in a thickness direction. The semiconductor element includes a main body and electrodes. The main body has a side facing the main surface of the conductor, and the electrodes each protrude toward the main surface from the side of the main body to be electrically connected to the main surface. The bonding layer is held in contact with the main surface and the electrodes. Each electrode includes a base portion in contact with the main body, and a columnar portion protruding toward the main surface from the base portion to be held in contact with the bonding layer, which is a sintered body of a metal powder.

A semiconductor device includes an electric conductor, a semiconductor element, and a bonding layer. The electric conductor has a main surface and a rear surface opposite to the main surface in a thickness direction. The semiconductor element includes a main body and electrodes. The main body has a side facing the main surface of the conductor, and the electrodes each protrude toward the main surface from the side of the main body to be electrically connected to the main surface. The bonding layer is held in contact with the main surface and the electrodes. Each electrode includes a base portion in contact with the main body, and a columnar portion protruding toward the main surface from the base portion to be held in contact with the bonding layer, which is a sintered body of a metal powder.

A semiconductor package structure includes a semiconductor die surface having a narrower pitch region and a wider pitch region adjacent to the narrower pitch region, a plurality of first type conductive pillars in the narrower pitch region, each of the first type conductive pillars having a copper-copper interface, and a plurality of second type conductive pillars in the wider pitch region, each of the second type conductive pillars having a copper-solder interface. A method for manufacturing the semiconductor package structure described herein is also disclosed.